The overarching goal of this research is to integrate family systems and developmental psychopathology theory and research to understand the processes underlying the association between destructive marital conflict and children's mental health with a specific emphasis on the role that sibling relationships play for understanding patterns of child adjustment and maladjustment. Destructive marital conflict poses significant risk to children's mental health and adjustment (for a review see Davies &Cummings, 1994) with significant implications for society. Moreover, sibling relations can either exacerbate child difficulties, or alternatively, promote positive child adjustment (for a review see Brody, 1998). Thus, high social importance is attached to understanding the role of sibling relations in the association between marital conflict and child outcomes. Toward this endeavor, there are four main aims of the proposed research. First, this research addresses theoretical and methodological gaps in the field. The sibling relationship literature has been heavily influenced by social learning theory (see Dunn &Davies, 2001;Jenkins, 1992;Stacker &Youngblade, 1999). As a result, the survey measures in the area commonly focus on warmth and conflict measures without consideration of family systems constructs. To address this gap, the first aim of the proposal is to develop and test the validity (i.e., predictive, discriminate, convergent) of a semi-structured interview assessment of sibling relationships based on family systems theory. Next, the processes by which marital conflict is associated with child psychopathology will be explored. Integrating family systems within sibling relationships and child psychopathology, the quality of children's sibling relationships will be examined in three models: additive (Aim 2), mediational (Aim 3), and moderator (Aim 4) to illuminate the link between marital conflict and child maladjustment. To test the proposed pathways, a multi-method, longitudinal study will be completed with children, their primary caregivers, and their teachers. This research complements and advances existing knowledge by (a) elucidating the impact of inter-parental discord on children's mental health;(b) examining children's sibling relations as potential processes that highlight the link between marital conflict and child maladjustment and;(c) incorporating an innovative assessment of children's sibling relationships designed to identify undetected patterns of sibling relations. PUBLIC HEALTH RELEVANCE: The multiple-method, multi- informant, and longitudinal design will yield a rigorous assessment of the study's main constructs. Results will be distributed and discussed as they pertain to future research and prevention/intervention efforts to enhance children's mental health.